Flexible clamp for paper cutters



Aug 7, 1962 l C.THUM1M 3,048,386

FLEXIBLE CLAMP FOR PAPER cUTTERs Filed Aug. l5, 1958 r EL E.

MMM/9% @445% Unite States Patent 3,048,386 FLEXIBLE CLAMP FR PAPER CUTTERS Carl Thumim, Westbury, NX., assigner, by mesne assignments, to Miehle-Goss-Dexter, Inc., Chicago, Ill., a corporation of Delaware Filed Aug. 15, 1958, Ser. No. 755,161 5 Claims. (Cl. 269-22) This invention relates to flexible clamps for paper cutters and more particularly to hydraulically powered clamps and the like.

In a copending application Serial No. 701,570, liled by the present applicant and assigned to the same assignee, there is disclosed and claimed a paper cutter clamp having a plurality of individually movable clamping elements which are actuated individually by hydraulic means. The present invention relates to generally the same subject matter and constitutes an improvement and simplification of the structure shown in the application referred to.

In general, the objects of the prior invention and of the present invention are substantially the same, viz., the provision of a hydraulically operated clamp having a plurality of separate clamping elements carried thereby for `engaging a paper pile in order to insure irm clamping at all points across the pile.

It is another object of the invention to provide a clamp having a plurality of pressure operated units which engage the paper and wherein the pressure exerted by the units is controlled by' the hydraulic pressure exerted on the clamp bar.

It is a further object of the invention to provide a paper clamp having a plurality of pressure applying units wherein such units are mounted so as to have a predeter mined degree of play or rocking in o-rder to conform to any irregularity along the line of clamping of the paper pile.

It is a still further object of the invention to provide a clamp having a plurality of pressure units wherein said units are capable of independent action although having a Common pressure supply.

It is yet a further object o-f the invention to provide a ice been known, but none of them have had the construction and the improvements afforded by the present invention and as set forth in the objects hereinabove, particularly wherein the present invention provides a flexible sole, socalled, which exerts a force along the clamping line that varies directly and automatically with the clamping force of the clamping bar.

Briey, my invention comprises the combination of a hydraulically operated clamping bar which may be conventionally mounted and actuated and which clamping bar carries a plurality of fluid (gaseous or liquid) oper-ated pressure feet wherein the iluid pressure, from a common source, is exerted within a flexible bag which is common to a plurality of pressure feet. Thus, a single, elongated ilexible pressure bag extends substantially the length of the clamping bar and through the clamping feet and is .disposed within the bar intermediate a lower internal wall thereof and the pressure feet. When fluid pressure is applied to the bag, the bag expands thus forcing the feet downwardly toward the paper pile. In-asmuch as the feet are separate elements, they engage the pile with substantially the same pressure at a plurality of points, depending upon the height of the pile beneath veach foot. Accordingly, a pile of non-uniform height will have equal pressure applied thereto' regardless of the non-uniformity.

A detailed description of my invention will now be given in conjunction with the appended drawing in which:

FIGURE l is a fragmentary elevation showing the essential components of the combination; and

FIGURE 2 is a section through 2 2 of FIGURE l.

Referring now to the drawing, a clamping bar 10 is disclosed formed with a narrowed lower guide portion or section 15 and carrying a plurality of clamping feet 20 of generally channel section and having flanges 22 provided with sliding co-action at the surfaces 24 with the guide portion 15. The feet 20 are each retained on the clamp having a pluralityI of, individual pressure-powered clamping units having a common pressure supply wherein the pressure of the supply varies with demand and may be controlled by the pressure of a separate supply which operates the clamp bar as disclosed in the aforementioned copending application Serial No. 701,570.

It is an additional object of the present invention to provide a clamp having a plurality of pressure operated units wherein the clamp construction is simple and rugged and requires a minimum of assembly and maintenance.

As is Well known, the thickness of the paper as it comes from the calendar rolls is not uniform across the Width. Thus, if there is a variation of .0001 inch, a pile of a thousand sheets will provide an irregularity up to la tenth of an inch. This irregularity occurs across the clamping line of the pile and it is therefore obvious that some parts of the pile along the clamping line will not be securely held. Thus, uneven cutting results.

Irregularity along the clamping line also occurs even with paper that is practically uniform in thickness, but which has been printed with heavy deposits of ink. The areas of heavy ink deposit are thicker than the imprinted areas; thus, uneven cutting again results.

It has heretofore been proposed to provide a clamp with a plurality of individually movable clamping feet which engage the paper pile and compensate for height irregularities. However, such prior art devices are principally of a type which rely on a plurality of springs and it has been found that this expedient is not entirely satisfactory. I am also aware that clamps having a plurality of hydraulically operated presser feet have heretofore clamping bar by means of a pair of pins 28 carried by the ilanges which pass through enlarged holes 32 provided in the guide section 15.

It will thus be apparent that each of the feet 20 has vertical play with respect to the clamp bar, which play is limited in upward direction by abutment of the edge top 36 of the side flanges of the feet with the shoulders 40 extending ho-rizontally `from guide portion 15. Play of the feet is limited in downward direction by engagement of pins 28 with the bottoms of bores 32.

The guide section 15 is foreshortened with respect to the bottom of the channel section of the feet so as to accommodate an elongated, flexible pressure bag 45 of any suitable material, such as reinforced neoprene.

A feed tube 48 connects to the bag and passes upwardly through the clamp bar and will be understood to be attached to a source of pressure. For example, where the clamp bar itself is actuated by hydraulic pressure, the same source of pressure may be conveniently utilized under suitable control for expanding the bag 45. The mode of control is not part of the present invention and it will be understood that any conventional kind of valving, either manual or automatic, may be utilized for feeding a pressure iluid to the bag 45.

Disposed between the bottom surface of the bag 45 and the bottom surface of the channel section o-f the feet is a flexible strip or plate 52 which extends throughout the feet. The flexible strip 52 may be of any suitable flexible material such as is used for a sole strip or plate 56. For example, I have found that a workable material for the strips 52 and 56 is heat treated spring metal.

The strip 52 need not be fastened to the feet, but merely reposes at the bottom of the channel sections and is maintained in position by the bag pressure. Preferably 3 the strip fills the full width of the channel. The sole strip 56 may be bolted to the bottom of the feet as by bolts 60.

It wil be apparent from the foregoing that when a pressure fluid is fed to bag 45, owing to the transverse constriction of the bag within the channel section of the feet, horizontal expansion is substantially prevented. However, the bag can expand vertically, thus pressing the individual feet downwardly against the paper' pile, each foot moving a distance determined by the thickness of the pile immediately below it. In the cross-section shown in FIGURE 2, the -foot 20 is shown at the lowermost extreme of motion withrrespect to the clamp bar i0, the pin 28 being shown bottomed in bore 32. Release of pressure in tube 48 will, of course, release the clamping force of the feet on a pile.

As seen in FIGURE 1, the feet 20 will be seen to be all identical and provided with upwardly tapering edges 63 on their front llanges. It will be understood that the rear llanges are provided with the same taper. Thus, the tapering clearance between opposed edges of adjacent feet avoid lateral pinching of the bag 45' where it passes between the feet, for at that point, the space is narrow enough to be bridged by the reinforcing material.

In the foregoing description, only such components as are necessary to a proper understanding of the invention by persons skilled in the art are disclosed and i1- lustrated. lIt will be apparent that the invention may be practiced in conjunction with any type of paper cutting machine or in any machine where a problem exists in the gripping of a pile of material which presents a certain amount of nonuniformity and wherein it is desired to have equal gripping pressure exerted on the pile. It will further be apparent that many changes may be made without departing from the spirit of the invention and I do not wish to be limited to the precise illustration herein given except as set `forth in the appended claims.

Iclaim:

1. In a clamp for a paper cutter, a bar, a plurality of presser feet carried by said bar, and means for actuating said feet with respect to said bar comprising an elongated pressure bag extending through a plurality of said feet and disposed intermediate said bar and said feet, and means for effecting pressure throughout said bag to expand said bag for actuating said feet, said feet being generally channel-like in section, and having opposed flanges and an internal bottom wall therebetween, said bar having a guide section extending between the opposed llanges of said feet; said opposed flanges being slidable relative said guide section, said guide section being foreshortened with respect to said internal bottom wall of each of said pressure feet, said foreshortened section having a bottom edge and said flexible bag being disposed between the bottom edge of said foreshortened section and the internal bottom wall of said feet, including means for retaining said feet on said guide section comprising pins extending between the flanges of individual feet, said guide section having bores of larger diameter than the diameters of said pins, said pins extending through respective bores, whereby play is afforded between said pins and said bores to permit relative motion between said feet and said guide section.

2. In a device as set forth in claim 1, said bar having shoulders disposed to be engaged by portions of said ilanges to limit motion of said feet in one direction, said pins bottoming in said bores to limit motion in the opposite direction.

f3. In a device as set forth in claim 1, said -tlanges having co-planar tapered edges effecting relative rockability of said feet, and a flexible reinforcing plate extending through said feet intermediate said flanges and disposed contiguously intermediate said bag and the internal bottom wall of each of said feet.

4. In a clamp for a paper cutter, a bar, a plurality of presser feet carried by said 4bar and having wall portions, means suspending said presser feet from said bar `whereby said presser feet are permitted individual lateral play and vertical play, means for actuating said feet with respect to said bar comprising an elongated pressure bag, means for effecting pressure in said bag, said bag extending through said presser feet and disposed intermediate said bar and said wall portions of said feet, and a flexible strip intermediate said bag and said wall portions of said feet whereby when pressure is introduced into said bag, said feet are moved away from said bar and wherein said flexible strip can extend across gaps intermediate said feet upon relative lateral movement thereof to prevent pinching of said bag therebetween.

5. In a clamp for a paper cutter, a bar having a bottom Wall, a plurality of individually movable presser feet having wall portions disposed below said bottom wall of said bar, a pressure bag disposed below said bottom wall and above said wall portions of said presser feet, and a llexible sole plate comprised of a continuous strip of material disposed intermediate said bag and said wall portions, and means for expanding said bag to individually move said presser feet relative said bar in respectively varying degrees dependent upon varying contour of work engaged by said presser feet, said sole plate flexing to maintain a smooth surface between said bag and said wall portions of said presser feet.

References Cited in the file of this patent UNITED STATES PATENTS 911,337 Seybold Feb. 2, 1909 1,881,185 Hazelton Oct. 4, 1932 2,556,305 Vickers June 12, 1951 2,600,127 Reaser et al June 20, 1952 FOREIGN PATENTS 388,891 Great Britain Mar. 9, 1933 

